Ship of Ghouls is a novella written by R. L. Stine. It was first published in 1999 and is the 36th book in the Give Yourself Goosebumps book series.
Description[]
Beware, reader -- this is no love boat! Your two-week cruise to Japan brings you face to face with a wacky scientist who turns humans into fish-like slaves, an evil stranger with a bomb, hostile natives, and sharks!